The present disclosure relates to a system and method for generating an output signal indicating a specific area on an optical disc, and more particularly, to a system and method for generating an output signal indicating a specific area on an optical disc utilizing an adjustable specific time.
An optical disc with pre-recorded address information (e.g., a DVD-RAM disc) includes different kinds of areas, as shown in FIG. 1, and which area is to be processed should be determined accurately while reading data from a target area or recording data onto the target area. Since the data field configuration is clearly defined in the DVD-RAM specification, further description is omitted here for the sake of brevity. As known to those skilled in this art, many operations should be performed before processing the target area, such as slicer reset, PLL adjusting, etc. When the target area to be processed can be determined as early as possible, the aforementioned operations can be performed more accurately, thereby increasing the accuracy of data reading or data recording.
Traditionally, two steps are necessary for generating desired output signals indicating specific areas of an optical disc with pre-recorded address information. One is utilizing an optical pick-up head signal and the other is utilizing pre-recorded address information commonly called Physic identification (PID) for a DVD-RAM disc. Because the pre-recorded address information cannot be obtained initially, the optical pick-up head signal is first utilized to generate output signals indicating specific areas of an optical disc, and then the pre-recorded address information is utilized.
However, optical pick-up head signals are usually unstable, meaning that the generation of pre-recorded address information may be affected due to undesired errors. Consequently, the output signals indicating specific areas of the optical disc according to the header signals and pre-recorded address information become unreliable thereby degrading the performance of the optical disc drive.
FIG. 2 and FIG. 3 are schematic diagrams illustrating the error due to erroneous optical pick-up head signals. As shown in FIG. 2, the correct output signal S1 is generated from the correct optical pick-up head signals C1 and C2, and the correct output signal S2 is generated from the correct optical pick-up head signals C3 and C4. However, if the erroneous optical pick-up head signals C5 and C6 occur, the erroneous output signal S3 is also generated from the wrong optical pick-up head signals C5 and C6. Similarly, as shown in FIG. 3, the optical pick-up head signals C7 and C8 that should be generated are not generated, and the corresponding output signal that should be generated is not generated, either. In the case described above, generation of the erroneous output signals may result in serious problems.
Therefore, a new method is needed to solve these problems.